Played a game last night that makes me wonder if the Expansion Rush might be unsound [see note below]. Clearly, a portion of the success I've had with it has been due in part to poor response by opponents. But last night I played against cb and he did just about everything right. Although he did try to retake his city (and failed), he then switched gears and rebuilt a new city to expand his econ. But he also built and garrisoned a tower right on the edge of the border, killing off the temple I had captured, and making it difficult for me to use my larger army effectively to threaten his other expansions and to expand my economy at his city. There were some other factors in his favor:

The expansion city was located in a low-lying area making it extremely difficult to defend once captured. He had the high ground over-looking the city

I was late getting to his city due to poor play on my part, so he managed to have some extra econ to support the later battles

His scout saw my troops on their way to his city, so he had ample time to prepare. He was unable to save his city, and I easily assimilated it, but he was more ready than I would have liked. This was clearly a case where a Capital Rush would have been a Miserable Failure

I was force to play with no sound and frequent wifey interruptions. I deal with the consequences, but it does make it more difficult to play effectively without the sound cues. We also had to pause the game for several minutes since my wife actually came into the room! WHEW! Only quick pausing and minimizing managed to save the day

Anyway, the conclusion is that he played well enough to thwart the Expansion Rush. So whether this may or may not be a viable strategy, we should all know how to play effectively to stop it. This game provides a good example. (I'll post the game later tonight.)

NOTE: I consider a strategy to be unsound when it is executed under ideal conditions and the opponent is still able to thwart it through best play. "Ideal conditions" means that your opponent has chosen a strategy that should lose to this strategy, the map and civ are conducive to attack, and you achieve the necessary level of surprise. "Best play" means your opponent chooses the correct strategy in response and executes satisfactorily. You can still win with unsound strategies, but this relies on your opponent being inept or choosing the wrong strategy in response . A sound strategy is one that wins against certain strategies even against best play by your opponent. (e.g., an ancient rush will defeat a straight boom, a boom defeats anti-rush, etc.) However, even unsound strategies can easily defeat you if you are not up to speed on how to effectively counter them. This discussion is useful because it helps us identify the proper response "on-the-fly" in future games. Which is not always that easy without some prior thinking.